Steel cord and article including the same

ABSTRACT

Steel cord and article including the same, the steel cord consisting of a center core and a plurality of outer strands twisted around the center core. The center core has a plurality of filaments or twisted strands which are arranged substantially in parallel to each other to form a parallel or non-twisted strand, thereby permitting the production processes to be greatly simplified while the mechanical properties of the steel cord are improved by virtue of the parallel strand forming the center core.

a] United States Patent 1 [1 1 3,726,078 Nakamura [4 Apr. 10, 1973 [54] STEEL CORD AND ARTICLE 3,336,744 8/1967 Peene ..57/145 INCLUDING THE SAL/[E 2,563,113 8/1951 Hindin et a1. ....57/l49 UX O [75] Inventor: Yoshimi Nakamura, Ashiya, Japan 5/1962 Fame: 57/145 [73] Assignee: Kobe Steel, Ltd., Fukiai-ku, Kobe, Primary Examiner--Wemer H. Schroeder Japan Attorney-Oblon, Fisher and Spivak 2 F' a 2] iled Sept 10, 1970 ABSTRACT 21 A LN 71,151 1 pp 0 Steel cord and article mcludmg the same, the steel cord consisting of a center core and a plurality of [52] US. Cl. ..57/145,S7/l49, 152/359 outer tr d twi ted around the center core. The Ill. center ore has a plurality of filaments o twisted [58] Field of Search ..57/3, l6, l7, l8, Strands which are arranged Substantially in parallel to 57/34 148; 152/356 359 each other to form a parallel or non-twisted strand, thereby permitting the production processes to be [56] References Cited greatly simplified while the mechanical properties of UNXTED STATES PATENTS the steel cord are improved by virtue of the parallel strand forming the center core. 1,312,872 8/19l9 Rettinger ..57/l45 3,209,528 lO/1965 Zerr ..57/l45 3 Clains, 7 Drawing PATENTED APR 1 01973 SHEET 1 BF 2 INVENTOR Yosuimi NAKAMURA d mmfl ATTOR NEYS PATENTEDAPRO'BB 3,726,078

SHEET 2 OF 2 INVENTOR YosHiMi NAKAMURA (95in MM a, Qfmk,

ATTORN EYS BACKGROUND OF THE INVENTION The present invention relates to a steel cord for reinforcing an article such as a rubber tire casing and a rubber belt and to the article including the same.

A prior art steel cord of the type described above consists in general of a center core formed by a plurality of strands twisted together and a plurality of outer strands twisted around the center core, each of the outer strands consisting of a center core formed by a filament or a strand and a plurality of outer strands each formed by a filament or a twisted strand and twisted around the center core of the respective outer strand of the steel cord.

In order to produce the outer strand to be twisted around the center core of the steel cord, a plurality of filaments or twisted strands must be twisted around a center core of the outer strand by means of a twisting machine. And the thus formed outer strands must be twisted around the center core of the steel cord by means of another twisting machine. Further, in case a plurality of twisted strands areused to form each of the outer strands of the steel cord, a still further twisting machine must be used to form the respective twisted strands to be twisted together for forming the outer strand.

Thus a plurality of processes are required to produce a prior art steel cord thereby resulting in a high cost and a time consuming work.

Consequently, the article such as a rubber tire and the rubber belt including the steel cord for reinforcing the same is made expensive.

The present invention aims at avoiding the above described disadvantages of the prior art.

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel and useful steel cord in which the disadvantages of the prior art steel cord are eliminated.

Another object of the present invention is to provide a novel and useful steel cord of the type described above which can be produced at a lower cost and still has superior mechanical properties.

A further object of the present invention is to provide a novel and useful steel cord of the type described above which, when embedded in a rubber article, has a high adhesive power to the rubber material.

The above objects are achieved in accordance with the present invention by the provision of a steel cord characterized by the center core including a plurality of filaments or a plurality of twisted strands which are arranged substantially in parallel to-each other to form a parallel or non-twisted strand around which a plurality of outer strands are twisted to form the steel cord.

Since the center core is in the form of a parallel or non-twisted strand, no twistsing machine is required to form the center core thereby permitting the cost for making the center core to be extremely lowered.

Further, the center core in the form of a parallel or non-twisted strands constructed in accordance with the present invention provides a lower loss of breaking load of the steel cord as well as a higher modulus of elasticity thereby permitting the breaking strength and fatigue to be improved.

Each of the outer strands may be formed by a filament or a twisted strand. The twisted strand forming the respective outer strand may further be formed by a plurality of filaments or a plurality of twisted strands.

A binding filament may be twisted around the finished steel cord so as to prevent the loosening thereof.

Each of the center core and the outer strands is preferably plated with brass so as to improve the adhesive power to the rubber material in an article in which the steel cord is embedded.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a general view partly broken showing a prior art steel cord;

FIG. 2 is a general view similar to FIG. 1 but showing a preferred embodiment of the steel cord of the present invention;

FIG. 3 is a cross-sectional view showing the construction of the embodiment of the present invention shown in FIG. 2; I

FIGS. 4 to 6 are cross-sectional views similar to FIG. 3 showing various modifications of the steel cord shown in FIG. 3; and

FIG. 7 is a cross-sectional view showing a rubber tire casing in which the steel cords of the present invention are embedded.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS ments 2 twisted together, a twisting machine is required to form center core 1 in addition to another twisting machine to twist outer strands 3 around center core 1 to form the steel cord thereby requiring a high cost and a time consuming work.

In contrast to the prior art steel cord shown in FIG. 1, the steel cord of the present invention comprises a center core 5 formed by a plurality of filaments 6 arranged substantially in parallel to each other so as to form a parallel or non-twisted strand 5 as shown in FIG. 2.

A plurality of strands 4 are twisted around center core 5 to form outer strands 3 in the similar manner as in the case of FIG. 1.

Since the center core is formed by a parallel or nontwisted strand, no twisting machine is required to form the center core so that the production cost is extremely reduced. In addition, the steel cord of the present invention provides a lower loss of breaking load as well as a high torsion value thereby permitting the mechanical properties such as the breaking strength and the fatigue resisting property to be increased due to the parallel arrangement of the filaments of the center core.

FIG. 3 shows the arrangement of the elements of the embodiment of the present invention shown in FIG. 2. The filament 6 is formed by three solid steel wires arranged substantially in parallel to each other and six solid steel wires 4 having a greater diameter than that of filament 6 are twisted around the center core formed by three filaments 6. A binding filament 7 is twisted around the steel cord so as to prevent the loosening of the steel cord. The number of filaments 6 and the number of outer strands 4 can be varied appropriately.

FIG. 4 shows a modification of the steel cord of FIG. 3. In this embodiment, the outer strands are constructed by six twisted strands 4' consisting of a center core formed by a filament having the same diameter as that of filament 6 of center core 5 and six filaments each having the same diameter as that of filament 6 and twisted around the center core of twisted strand 4'. Since all the filaments are of the same diameter the preparation of the filaments is simplified to lower the production cost.

FIG. 5 shows a further modification of the steel cord of FIG. 3. In this embodiment, outer strands 4" are constructed by six twisted strands 9 having a center core formed by a twisted strand l0 and six twisted strands 10 twisted around the center core.

FIG. 6 shows a still further modification of the steel cord of FIG. 3. In this embodiment, the center core is formed by three twisted strands 11 arranged substantially in parallel to each other so as to form a center core in the form of a parallel or non-twisted strand, while the outer strands 4 are formed by six filaments having a greater diameter than that of the twisted strands forming the center core.

It is apparent that the outer strands may be formed by a plurality of twisted strands as shown in FIG. 4 and 5 while the mechanical properties are sufficiently maintained.

FIG. 7 shows a rubber tire in which the steel cords of the present invention are embedded so as to reinforce the tire. In FIG. 7, rubber tire casing 12 comprises a single carcass ply 14 embedded in tire casing 12 and a breaker ply 15 embedded adjacent to tread portion 13 of tire casing 12 and a plurality of crown or head plies 16, 17 and 18 embedded in tire casing 12 between breaker ply 15 and carcass ply 14. Plies 15, 16, 17 and 18 include a plurality of steel cords described in connection with FIGS. 2 to 6.

Steel cord 19 may also be embedded in tire casing 12 so as to reinforce the longitudinal edge portion of carcass ply 14.

In order to increase the bonding power of the steel cord to the rubber material of tire casing 12, brass-plating is preferably applied to each of the center core and the outer strands of the steel cord of the present invention.

I claim:

1. Article comprising rubber material and a plurality of steel cords embeded therein for increasing the mechanical strength of said article, wherein the improvement comprises the fact that said steel cord consists of a center core including three filaments arranged substantially parallel to each other and six outer strands twisted around said center core, the lay of twist of all of said outer strands extending in one direction and the diameter of each of said six outer strands being greater I than the diameter of each of said three center core fila- 3. A steel cord comprising a center core formed of ree filaments arranged in substantially parallel relation to provide a parallel, untwisted strand; and

six outer strands twisted in the same direction around said center core,

the diameter of each of said six outer strands being.

greater than the diameter of each of said three center core filaments. 

1. Article comprising rubber material and a plurality of steel cords embeded therein for increasing the mechanical strength of said article, wherein the improvement comprises the fact that said steel cord consists of a center core including three filaments arranged substantially parallel to each other and six outer strands twisted around said center core, the lay of twist of all of said outer strands extending in one direction and the diameter of each of said six outer strands being greater than the diameter of each of said three center core filaments.
 2. Article according to claim 1 wherein each of said three filaments of said center core of said steel cord consists of three twisted strands arranged substantially in parallel relation to each other.
 3. A steel cord comprising: a center core formed of three filaments arranged in substantially parallel relation to provide a parallel, untwisted strand; and six outer strands twisted in the same direction around said center core, the diameter of each of said six outer strands being greater than the diameter of each of said three center core filaments. 